feat: complete hosted mod sync and launcher interface updates

Add pack sync markers, tagged mod updates, parallel progress, JWT downloads and retry recovery. Include pending onboarding, about scene, compatibility data pack and download fixes.

apps/app-frontend/src/helpers/hosted-download-failures.test.ts

@@ -0,0 +1,51 @@
+import assert from 'node:assert/strict'
+import test from 'node:test'
+import { createHostedDownloadFailures } from './hosted-download-failures.ts'
+
+test('retry clears only its own failure before progress arrives and ignores late old events', () => {
+	const state = createHostedDownloadFailures()
+	const failed = (instanceId: string, loader: string, error: string) => ({
+		fraction: null,
+		loader_uuid: loader,
+		event: { type: 'hosted_pack_sync', instance_id: instanceId, instance_name: instanceId, error },
+	})
+	const oldFailure = failed('one', 'old', 'old failure')
+	state.update(oldFailure)
+	state.update(failed('two', 'other', 'other failure'))
+	state.begin('one', state.values())
+	assert.equal(state.has('one'), false)
+	assert.equal(state.has('two'), true)
+	assert.equal(state.isRetired('old'), true)
+	state.update(oldFailure)
+	assert.equal(state.has('one'), false)
+	state.update(failed('one', 'new', 'new failure'))
+	state.update({ ...oldFailure, fraction: 0.5 })
+	assert.equal(
+		state.values().find((bar) => bar.bar_type?.instance_id === 'one')?.message,
+		'new failure',
+	)
+})
+
+test('a new native task retires the previous failed task without a frontend retry', () => {
+	const state = createHostedDownloadFailures()
+	const old = {
+		fraction: null,
+		loader_uuid: 'old',
+		event: { type: 'hosted_pack_sync', instance_id: 'instance', error: 'old failure' },
+	}
+	state.update(old)
+	state.update({ fraction: 0, loader_uuid: 'new', event: { ...old.event, error: null } })
+	state.update(old)
+	assert.equal(state.has('instance'), false)
+})
+
+test('late failure from an older active task cannot replace the new task', () => {
+	const state = createHostedDownloadFailures()
+	const event = { type: 'hosted_pack_sync', instance_id: 'instance' }
+	state.update({ fraction: 0.5, loader_uuid: 'old', event })
+	state.update({ fraction: 0, loader_uuid: 'new', event })
+	state.update({ fraction: null, loader_uuid: 'old', event: { ...event, error: 'old failure' } })
+	assert.equal(state.has('instance'), false)
+	assert.equal(state.isRetired('old'), true)
+	assert.equal(state.isRetired('new'), false)
+})